1. Technical Field
The present invention relates to a method for manufacturing a liquid ejecting head.
2. Related Art
Mentioned as a liquid ejecting apparatus having a liquid ejecting head is, for example, an ink jet recording apparatus provided with an ink jet recording head having a plurality of pressure generating chambers which generate pressure for ejecting ink droplets by a piezoelectric element or a heat generating element, a common reservoir which supplies ink to each pressure generating chamber, and a nozzle opening communicating with each pressure generating chamber. The ink jet recording apparatus is configured so that a discharge energy is applied to ink in the pressure generating chamber communicating with a nozzle corresponding to a printing signal to discharge the ink from the nozzle opening.
JP-A-2007-261215 discloses a method for manufacturing an ink jet recording head. According to the manufacturing method, a plurality of piezoelectric element materials are formed into films on one surface side of a flow path forming substrate containing a silicon substrate to thereby form a piezoelectric element, a reservoir forming substrate having a reservoir portion is joined to the one surface side of the flow path forming substrate, and thereafter a mask having a predetermined shape is formed on the other side of the flow path forming substrate and anisotropic etching is performed, thereby forming a liquid flow path containing pressure generating chambers and a communication portion.
In the former technique, silicon nitride (Si3N4) in which a size variation due to undercutting during etching is smaller than that of silica dioxide (SiO2) is employed as the mask in the anisotropic etching technique. The mask has a small film thickness and patterning is performed by dry etching, and therefore the dimension accuracy is good.
However, in order to remove a mask film in the shape of eaves generated after the anisotropic etching, it is necessary to perform wet etching, and phosphoric acid (H3PO4) is used as an etchant therefor. Phosphoric acid has a risk of damaging an adhesive or the like for joining the substrates, and therefore can cause a reduction in the head quality. In order to avoid the risk, a measure for lowering the wet etching temperature can also be taken. However, the treatment time is prolonged, and therefore mass productivity is poor.
Therefore, it has been desired to employ another new mask in the anisotropic etching technique.